The grain hauling business is a very large business with the majority of grain, or other particulate materials being hauled by truck, railroad car or barges. Particularly for grain products, certain standards of inspection must be complied with and the price of the product is directly affected by the quality of the product. For example, the grain must have a moisture content not exceeding specified limits, the grain must not be adulterated with foreign materials to any large extent, the grain must be in good healthy condition and not rotted, and so on. Accordingly, samples are taken from the transporting vehicle in order to determine the quality of the grain in that vehicle.
Obviously, the sampling technique is only valid if the sample taken is truly representative of the grain or other particulate material contained in the hauling vehicle. Since it is not practical for the purchaser to inspect all of the grain, it is critically important that the samples which are taken are in fact truly representative in order that the quality of the hauled product can be determined.
Typically, in sampling at least two samples are taken. This is important in that a second sample can be a check on the representative accuracy of the first sample. Thus, if both samples are within reasonable limits identical, one can safely assume that the samples are a reasonably accurate representation of the entire contents of the hauling vehicle.
Experience with the hauling of grains has demonstrated that grain products often will sift and settle during shipment with the multi-fines shifting to the bottom portion of the container, with larger and bulkier materials occupying correspondingly higher positions within the particulate material load. For example, if the grain is corn, the multi-fines or smallest products typically will shift towards the bottom of the load, any foreign material such as portions of the stock and leaves will be at an intermediate position, and the larger, more bulky grain kernels will be at the top of the load. This shifting is typical for all loose particulate materials. Thus, it is important that a grain sampling probe which penetrates the load obtains a truly representative sample of every portion of the grain product through which it is penetrating. In other words, the core sample which is removed must have a respresentative amount of each type of material present at each different level within the grain load. For example, if the grain probe receives large amounts of the finest material from the bottom portion of the load, the removed core sample will be disproportionately high in fines and not be truly representative of the material in the vehicle load.
For the most part, grain sampling has been done on a commercial basis, manually. This is tedious and time consuming. Therefore, in recent years there have been some attempts at developing powered probes which can automatically sample a load of particulate material. However, heretofore such automatic sampling devices have not been able to obtain truly representative core samples of the bulk material being sampled. Therefore, automatic sampling devices have not met with a great deal of success in that they have not had the ability to duplicate the accuracy of manual sampling techniques. For example, Larson, U.S. Pat. No. 3,789,671 issued Feb. 5, 1974, relates to an automatically powered grain probe which utilizes hydraulic means to move the grain probe upwardly and downwardly within the bulk material which is being sampled. Such a device does not obtain a truly accurate sample because hydraulic powered systems will not move at a uniform rate of speed upwardly and downwardly within the bulk material.
There are several reasons why the hydraulically operated probe will not obtain a uniform sample. The bulk of the grain surrounding the probe after it is inserted into a load, causes significant resistance to the withdrawal of the probe; and, this resistance will cause eratic jerking movements of a hydraulically powered probe. Thus, when the force of the hydraulic fluid is applied against the piston of the hydraulic cylinder to cause withdrawal of the probe, typically a greater force must be applied initially in order to overcome the resistance of the grain pressing inwardly against the probe than after the probe has started movement. Therefore, there is a tendency for the probe to initially jerk rapidly through the grain sample as it is being withdrawn and thereafter to move at a slower rate of speed. As a result, since the grain sample is sucked within the probe during withdrawal, the sample that is obtained is not truly representative. Additionally, probes which are operated by hydraulic powered means during the probe withdrawal are susceptible to variance in withdrawal speed at different climatic conditions because the viscosity of the hydraulic fluid will change. As a result, hydraulic operated probes do not function very effectively in locations which are subjected to a wide variety of outdoor climactic conditions.
It is a primary object of this invention to develop a grain probe which does not utilize hydraulic means to power the probe during withdrawal from a grain load and which will obtain a truly representative core sample of a load of bulk material.
Another important object of this invention is to provide a grain probe which is powered solely by mechanical drive means in order to allow a uniform rate of withdrawal speed.
Another object of this invention is to provide a grain probe which may be installed out of doors and operate without any significant sensitivity to change in climactic conditions.
Still another object of this invention is to provide a mechanical grain probe which will obtain uniform samples regardless of the resistance caused by the inward pressing of the bulk material against withdrawal of the probe after it has been inserted into a load of material.
A still further object of this invention is to provide a probe which utilizes an extendable arm assembly in order that an operator may have greater latitude in adjustment of the lateral distance between the sampling device and a load hauling vehicle.
A still further object of this invention is to provide a sampling device which will allow better operator control to swing through an entire 180 degree arc with the ability to stop at any position within that arc in order to take a sample at any desired location within a load of particulate material.
A still further object is to provide a mechanical grain probe which exists as a free standing unit with no need for any support other than at the base of the device.
The method and means of accomplishing the results of this invention will become apparent from the detailed description of the invention which follows.